ABSTRACT
The Coat protein and Maturase gene of E.coli bacteriophage MS2 was amplified by PCR,then the gene was cloned into pET32a to construct the intermediate vector pET32aCP.The conservative sequence of FMDV internal ribosome entry site(IRES) was cloned into the downstream of pET32aCP bacteriophage gene to construct the prokaryotic expression vector pCPES.The recombinant plasmid pCPES transformed into E.coli strain BL21(DE3) was induced to express with 1mmol/L IPTG.The expression products were purified by sucrose density gradient centrifugation.The expression products observed by TEM were circular viruslike particles,and the diameter of these particles was about 26nm.The stability of viruslike particles was detected,and the viruslike particles was identified by RTPCR.The results showed that the viruslike particles contain the FMDV IRES RNA and have good stability.The viruslike particles have great prospect as the standard and quality control in the area of RNA virus detection.
ABSTRACT
The fused gene (PTH-TFN) of parathyroid hormone (PTH) gene and transferring N-terminal half-molecule (TFN) gene was amplified by multiple PCR and inserted into pPIC9 vector. The recombinant plasmid pPIC9-PTH-TFN was transformed into Pichia pastoris GS115 by PEG. After methanol induction, the target protein was expressed in fermentation supernatant at high level. The fused protein PTH-TFN with purity being higher than 95% was finally obtained after purification through two-step chromatography: SP Sepharose Fast Flow and Phenyl Sepharose Fast Flow. Western blot analysis and adenylate cyclase assay proved that the fused protein exhibited the bioactivity to stimulate cAMP synthesis and the ability to bind Fe3+ in the Fe3+ saturation study as the recombinant TFN did indicating that TFN could be used as the transcellar carrier of PTH.